DE102017006289A1 - Microfiber composite fabric - Google Patents

Abstract

The invention relates to a microfiber composite nonwoven fabric comprising at least one layer S containing a first fiber component and at least one layer M containing a second fiber component, wherein the second fiber component has at least partially penetrated into the layer S, wherein the fibers of the first fiber component melt-spun and nonwoven composite filaments which are at least partially split into elementary filaments having an average titer of less than 1 dtex, and solidified, the fibers of the second fibrous component being meltblown fibers.

Description

The invention relates to a microfiber composite nonwoven fabric. The invention further relates to the production of such a composite nonwoven fabric, as well as its use.

Nonwovens are advantageous for many applications. Nonwovens are structures of limited length fibers, filaments or cut yarns of any kind and of any origin that have been assembled in any manner into a sheet, nonwoven, nonwoven, fibrous, batt, and bonded together in any way; this excludes the interlacing or weaving of yarns, such as weaving, knitting, knitting, lace making, braiding and making tufted products. Nonwoven fabrics can be made in a wide variety of ways, for example by means of mechanical, aerodynamic and / or hydrodynamic processes.

An essential parameter of nonwovens is their pore size distribution. Application specific are nonwovens with suitable pore size distribution and suitable air passage resistance, for example, as a component of soundproofing in construction, of sound insulation in motor vehicles, as a barrier layer in home textiles (mite-dense products, hypo-allergenic bedding, cleaning media), as packaging material or filter media used.

Up to now, non-woven fabrics made of split microfibers have been used for these applications. Although microfiber nonwovens have a suitable for various applications pore size distribution combined with very good functionalities, but their manufacturing process is technically relatively complex particularly for the production of materials with uniform and homogeneous pore size distribution and often requires the use of high basis weights. However, as the basis weight increases, achieving the high split levels necessary for microfiber properties becomes increasingly difficult.

When using alternative materials, such as films, specialty papers or meltblown fibers, however, often the profile of the mechanical properties is insufficient.

Presentation of the invention

The object of the invention has been found to provide a nonwoven fabric which eliminates the aforementioned disadvantages, at least in part.

• - die Fasern der ersten Faserkomponente schmelzgesponnene und zu einem Vlies abgelegte Verbundfilamente sind, die zumindest teilweise zu Elementar-Filamenten mit einem mittleren Titer von weniger als 1 dtex, gesplittet und verfestigt sind,
• - die Fasern der zweiten Faserkomponente Schmelzblasfasern sind.

According to the invention, the object is achieved by a microfiber composite nonwoven comprising at least one layer S containing a first fiber component and at least one layer M containing a second fiber component, wherein the second fiber component has at least partially penetrated into the layer S and wherein

• the fibers of the first fiber component are melt spun and nonwoven composite filaments which are at least partially split into elementary filaments having an average titer of less than 1 dtex, and solidified,
• - The fibers of the second fiber component are meltblown fibers.

Hereinafter, the composite filaments split at least partially into elementary filaments having an average titer of less than 1 dtex are also referred to for short as "split fibers".

The microfiber composite nonwoven according to the invention is characterized in that it contains split fibers in synergistic combination with meltblown fibers.

According to the invention, it has been found that a nonwoven fabric with a low average pore diameter of preferably less than 20 .mu.m, for example from 7 .mu.m to 17 .mu.m, more preferably from 9 .mu.m to 17 .mu.m can be obtained by the special combination of split fibers with the meltblown fibers. In this case, the smallest pore diameter found may preferably be less than 11 μm, for example from 5 μm to 10 μm, more preferably from 2 μm to 6 μm.

An inventive microfiber composite nonwoven fabric with the aforementioned small pore diameters has the advantage that it is also at relatively low basis weights, for example in having a basis weight of less than 300 g / m ² , high fractional separation efficiencies. This allows the advantageous use, for example, as a filter medium or in the field of allergy-appropriate textiles.

At the same time excellent mechanical properties are found, especially under hot conditions. In addition, the special combination of split fibers with meltblown fibers proves to be unexpectedly favorable, especially in terms of sound absorption. In a microfiber composite nonwoven according to the invention, a surprising synergistic effect of split fibers and meltblown fibers is shown when considering the sound absorption. The sound absorption coefficient is clearly above the range that would be expected by pure combination of the starting materials or evaluation of the air passage resistance to be measured. This result was particularly surprising insofar as it was actually to be expected that the strong barrier effect usually produced by meltblown fibers leads to disproportionately high air passage resistance, which should prove unfavorable for producing a balanced sound absorption profile.

Without specifying a mechanism, it is assumed that the good performance of the nonwoven fabric according to the invention for sound absorption and as a filter medium is achieved by the at least partial penetration of the fiber component of the layer M into the layer S. According to the invention, the meltblown fibers at least partially penetrate the layer S having split fibers. In this case, a further thorough mixing of the layers may be present in that both fiber components at least partially penetrated into the respective other layer and / or a complete mixing of the fiber components of the layers S and M is present. This effect can be achieved, for example, by first forming a layer composite S'M 'or even larger layer composites (eg S'M'C) and then carrying out a hydroentanglement step for the entire layer composite in which apart from the mixing it is expedient at the same time to split or split Solidification takes place. It has been found that by means of hydroentanglement both layers can be joined together in one step and that no further split or subsequent solidification steps are required. Thus, in hydroentanglement, the composite filaments used to make the ply S may be split and, at the same time, the meltblown fibers in the Z direction, i. in the direction of the cross section of the nonwoven fabric. Similarly, the split composite filaments used in layer S may also be in the Z direction, i. in the direction of the cross section of the nonwoven fabric. Depending on various parameters, such as the pressure used in the hydroentanglement, the layer thickness and the stickiness of the meltblown fibers, this can lead to a more or less uniform distribution of the meltblown fibers in the layer S up to a complete mixing of the two layers. This variability can be used to specifically modify property profiles of the composite material.

Thereby, e.g. usually negatively evaluated properties of individual layers of the composite are compensated. For example, after joint hydroentanglement of meltblown fibers and composite filaments, a significantly higher abrasion resistance of the surface can be observed, depending on parameters, than would be expected for a surface consisting solely of meltblown fibers.

According to the invention, the first fiber component has melt-spun composite filaments deposited to form a nonwoven. The term filaments according to the invention are understood to mean fibers which, unlike staple fibers, have a theoretically unlimited length. Composite filaments consist of at least two elementary filaments and can be split and solidified into elementary filaments by conventional grit methods such as water jet needling. The composite filaments of the first fiber component according to the invention are at least partially split into elementary filaments.

Also preferably, the titer of the composite filaments before splitting is 1.5 to 3.5 dtex, more preferably 2.0 dtex to 3.0 dtex, and / or the denier of the elementary filaments is 0.01 dtex to 0.8 dtex , preferably from 0.03 dtex to 0.6 dtex and in particular from 0.05 dtex to 0.5 dtex.

Preferably, the composite filaments have at least two incompatible polymers. Such composite filaments show good splittability in elementary filaments and cause a favorable ratio of strength to basis weight.

In order to achieve a suitable pore size distribution with sufficient mechanical strength, it is advantageous if the proportion of the elementary filaments of the first fiber component, based on the total weight of the nonwoven fabric (as sum value across all composite layers) is at least 20% by weight. Practical experiments have shown that a particularly balanced property profile between porosity and mechanical properties can be generated if the proportion of these elementary filaments of 20% by weight to 60% by weight, in particular from 30% by weight to 50% by weight, based on the total weight of the composite nonwoven fabric.

With regard to the individual layers of the nonwoven fabric, it is advantageous if the proportion of the elementary filaments of the first fiber component in the respective layer S, for example in an outer layer S or in an inner layer S of 80 wt.% To 100 wt.% , preferably from 90% by weight to 100% by weight, in particular 100% by weight, in each case based on the total weight of the layer S.

With regard to abrasion resistance or pilling of the surface, it is advantageous if at least one outer layer of the nonwoven fabric is formed by the layers S.

An advantage of the use of composite filaments as starting material for producing the elemental filaments is that the titer of the elementary filaments produced from them can be adjusted in a simple manner by varying the number of elementary filaments contained in the composite filaments. In this case, the titer of the composite filaments can remain constant, which is advantageous in terms of process technology. Another advantage of using the composite filaments is that in addition the ratio of thicker and thinner filaments in the nonwoven fabric can be controlled in a simple manner by varying the degree of splitting of the composite filaments.

The elementary filaments can be formed in cross-section circular segment-shaped, n-sided, or multilobal.

Preferably, the composite microfiber nonwoven fabric of the present invention is one in which the composite filaments have a cross-section of orange-slit-like or "pie" multisegment structure, which segments may contain various alternating incompatible polymers. Also suitable are hollow-pie structures that can also have an asymmetrically axially extending cavity. Pie structures, in particular hollow-pie structures, can be split particularly easily.

With regard to the first fiber component, the orange-slit or pie-pie arrangement advantageously has 2, 4, 8, 16, 24, 32 or 64 segments, particularly preferably 16, 24 or 32 segments.

In order to obtain easy splittability, it is advantageous if the composite filaments comprise filaments which contain at least two thermoplastic polymers. Preferably, the composite filaments comprise at least two incompatible polymers. Incompatible polymers are to be understood as meaning those polymers which in combination do not give only limited or poorly adhering pairings. Such a composite filament has a good cleavability in elementary filaments and causes a favorable ratio of strength to basis weight.

As incompatible polymer pairs, polyolefins, polyesters, polyamides and / or polyurethanes are preferably used in such a combination that does not result in only limited or difficultly adhesive pairings.

The polymer pairs used are particularly preferably selected from polymer pairs with at least one polyolefin and / or at least one polyamide, preferably with polyethylene, such as polypropylene / polyethylene, polyamide 6 / polyethylene or polyethylene terephthalate / polyethylene, or with polypropylene, such as polypropylene / polyethylene, polyamide 6 / polypropylene or polyethylene terephthalate / polypropylene.

Very particular preference is given to polymer pairs with at least one polyester and / or at least one polyamide.

Polymer pairs with at least one polyamide or with at least one polyethylene terephthalate are preferred because of their conditional bondability, and polymer pairs with at least one polyolefin are particularly preferably used because of their poor bondability.

Polyesters, preferably polyethylene terephthalate, polylactic acid and / or polybutylene terephthalate on the one hand, polyamide, preferably polyamide 6, polyamide 66, polyamide 46 on the other hand, if appropriate in combination with one or more further polymers which are incompatible with the abovementioned components, have been preferably selected as particularly preferred components made of polyolefins as special proved appropriate. This combination has excellent cleavability. The combination of polyethylene terephthalate and polyamide 6 or of polyethylene terephthalate and polyamide 66 is very particularly preferred.

To design a microfiber composite nonwoven fabric according to the invention, it is advantageous if at least one of the components used in the composite filaments of layer S is also used as raw material for producing the meltblown fibers of layer M.

In order to obtain a composite nonwoven having high strength, the composite filaments of the layer S may also have a latent or spontaneous crimp resulting from an asymmetric structure of the elementary filaments with respect to their longitudinal central axis, which crimping may be due to an asymmetrical geometrical configuration of the cross section the composite filaments is activated or reinforced. As a result, the nonwoven fabric can be provided with a high thickness, a low modulus and / or a multi-axial elasticity.

In a variant, the composite filaments of the layer S may have a latent or spontaneous crimp due to a differentiation of the physical properties of the polymer filaments forming the elementary filaments in the spinning, cooling and / or stretching operations involving the composite filaments, which leads to twisting. which are caused by internal unbalanced loads with respect to the longitudinal center axis of the composite filaments, wherein the crimping is optionally activated or reinforced by an asymmetric, geometric configuration of the cross section of the composite filaments.

The composite filaments may have a latent crimp which is activated by thermal, mechanical or chemical treatment prior to forming the composite nonwoven fabric.

According to a preferred embodiment of the invention, the composite filaments are dyed by spin dyeing.

According to the invention, the second fiber component comprises meltblown fibers. By the term meltblown fibers is meant fibers made by extruding a molten thermoplastic material through a plurality of fine, usually circular die capillaries as molten fibers into a high velocity gas (e.g. air). By doing so, the diameter of the fibers is reduced. Thereafter, the meltblown fibers are carried by the high velocity gas stream and deposited on a collecting surface to form a web of randomly distributed fibers. The melt-blowing process is well known and disclosed in various patents and publications, for example, NRL 4364, "Preparation of Superfine Organic Fibers" by VA Wendt, EL Boone and CD Fluharty; NRL Report 5265, "An Improved Device for the Formation of Superfine Thermoplastic Fibers" by KD Lawrence, RT Lukas, and JA Junge; and US Pat. 3,849,241 , issued November 19, 1974 to Buntin, et al. These documents are hereby incorporated by reference for reference.

In a further preferred embodiment of the invention, the meltblown fibers are formed from polymers selected from the group consisting of: polyesters, polyolefins, polyamides and polyurethanes, copolymers and / or mixtures thereof.

In a particularly preferred embodiment of the invention, the raw material of the meltblown fibers used is a thermoplastic, spinnable or injection-processable raw material, in particular selected from polyolefins, copolyolefins, polyesters, copolyesters, polyurethanes, polyamides and / or copolyamides having an MFI value (melt flow index , Melt flow index) ISO 1133 from 100 to 3000 g / 10 min.

Due to the low viscosity of the raw material used to make meltblown fibers, filaments with very low titers can be made under appropriate processing conditions. This favors the mixing of the layers in the split process, whereby an undesirable delamination between the layers can be prevented and thus composites with high mechanical strength arise.

In a further preferred embodiment of the invention, the meltblown fibers have a fiber titer of from 0.5 μm to 5 μm, preferably from 1.0 μm to 4 μm, in particular from 1.8 μm to 3.6 μm. An advantage of this embodiment is that a particularly homogeneous nonwoven composite can be produced with regard to the pore size distribution, since defects in the layer S are more compatible with meltblown fibers Design can be completed. When using the microfiber composite nonwoven fabric as filter material, this leads to particularly good fractional separation degrees of particles in the range from 0.5 μm to 10 μm.

The proportion of meltblown fibers in the microfiber composite nonwoven fabric is preferably at least 20% by weight, more preferably from 40% to 60% by weight, especially from 45% to 55% by weight, based in each case on the total weight of the microfiber composite nonwoven fabric ,

It is conceivable that the at least one layer S and / or M has, in addition to the respective fiber component (split fibers and / or meltblown fibers), further components, for example further fibers. It is also conceivable that the microfiber composite nonwoven fabric from more than two layers, for example, with the additional use of additional layer S and / or M, Stapelfaservliesen and / or other non-textile fabrics is constructed. Thus, according to the invention, the microfiber composite nonwoven fabric may comprise, in addition to the layers S and M, at least one further layer C containing, for example, staple fibers and / or continuous fibers (filaments) containing preferably synthetic fibers such as aramid fibers and / or natural fibers, or more preferably they exist. In a preferred embodiment of the invention, the fibers and / or filaments of the layers S, M and / or C penetrate each other at least partially.

Advantageously, the at least one further layer C forms one and / or both outer layers of the microfiber composite nonwoven fabric.

By integrating further layers C, depending on the size, type and raw material used in the fiber component, further functionalities can be generated, e.g. allow a progressive construction or flame retardant surfaces.

It is also conceivable that the at least one further layer C is designed as a reinforcing layer, for example in the form of a scrim, and / or that it comprises woven fabric, knitted fabric and / or scrim. It is basically conceivable that the at least one further layer C forms the outer layer (s) of the nonwoven fabric. Advantageously, however, the at least one further layer C is arranged such that a progressive structure with respect to the fiber fineness arises in the cross section of the microfiber composite nonwoven fabric. As a result, the different fiber cross sections / thicknesses gradually merge into each other.

The polymers used to produce the filaments of the composite nonwoven fabric may contain at least one additive selected from the group consisting of color pigments, antistatic agents, antimicrobials such as copper, silver, gold, or hydrophilization or hydrophobing additives in an amount of 150 ppm to 10% by weight. , contain. The use of said additives in the polymers used allows adaptation to customer-specific requirements.

The basis weights of the composite nonwoven fabric according to the invention are adjusted depending on the desired application. As appropriate for many applications, basis weights, measured according to DIN EN 29073, in the range of 40 g / m ² to 300 g / m ² , preferably from 50 g / m ² to 150 g / m ² , and in particular of 70 g / m ² to 130 g / m ² proved. In this case, the basis weight of the layer S is advantageously from 30 g / m ² to 250 g / m ² , preferably from 40 g / m ² to 100 g / m ² , and / or the basis weight of the layer M is 10 g / m ² to 100 g / m ² , preferably from 20 g / m ² to 60 g / m ² .

Further preferably, the composite nonwoven fabric has a thickness DIN EN ISO 9073-2 from 0.1 mm to 3.0 mm, preferably from 0.15 mm to 2.5 mm, in particular from 0.2 mm to 2 mm.

More preferably, the composite nonwoven fabric has a degree of sound absorption (1000 Hz) of more than 0.4, for example from 0.4 to 0.8 and / or more than 0.5, for example from 0.5 to 0.7 and / or of more than 0.6, for example from 0.6 to 0.7, in each case preferably at a weight per unit area below 150 g / m ² , more preferably below 130 g / m ² , in particular below 100 g / m ² .

Also preferably, the composite nonwoven fabric has a sound absorption level (2000 Hz) of greater than 0.8, for example from 0.8 to 1.0 and / or greater than 0.85, for example from 0.85 to 1.0 and / or from more than 0.9, for example from 0.9 to 1.0, in each case preferably at a weight per unit area below 150 g / m ² , more preferably below 130 g / m ² , in particular below 100 g / m ² .

Also preferably, the composite nonwoven fabric has a sound absorption level (3000 Hz) greater than 0.8, for example from 0.8 to 1.0 and / or greater than 0.85, for example from 0.85 to 1.0 and / or from more than 0.9, for example from 0.9 to 1.0, in each case preferably at a weight per unit area below 150 g / m ² , more preferably below 130 g / m ² , in particular below 100 g / m ² .

Also preferably, the composite nonwoven fabric has a mean flow pore diameter of less than 20 microns, for example from 5 microns to 20 microns, more preferably less than 18 microns, for example from 6 .mu.m to 18 .mu.m, and in particular less than 17 .mu.m, for example 7 microns to 17 microns, each preferably at a basis weight below 200 g / m ² , more preferably below 150 g / m ² , in particular below 100 g / m ² .

Also preferably, the composite nonwoven fabric has a fractional efficiency (particle size 1-4.7 mm) of greater than 60%, for example from 60% to 100%, more preferably greater than 75%, for example from 75% to 100%, and most preferably greater than 90%, for example from 90% to 100%.

Also preferably, the composite nonwoven fabric has a Fraktabscheidegradrad (particle size> 5 mm) of more than 80%, for example from 80% to 100%, more preferably more than 85%, for example from 85% to 100%, and in particular more than 90% For example, from 90% to 100%.

Also preferably, the composite nonwoven fabric has a hot tensile elongation in the longitudinal direction (180 ° C) of more than 50%, for example 50% to 85% and / or 50% to 80%, more preferably more than 60%, for example 60% 85% and / or from 60% to 80% and in particular more than 65%, for example from 65% to 85% and / or from 65% to 80%.

Also preferably, the composite nonwoven fabric has a hot tensile elongation in the transverse direction (180 ° C) of more than 55%, for example 55% to 95% and / or 50% to 90%, more preferably more than 65%, for example 65% 95% and / or from 65% to 90% and in particular more than 75%, for example from 75% to 95% and / or from 75% to 90%.

Also preferably, the composite nonwoven fabric has a three-dimensional deformability in the hot state (OTI test, 160 ° C), determined as path length to damage in cm, of at least 8 cm, for example 8 cm to 12 cm, preferably at least 9 cm, for example 9 cm to 12 cm, more preferably at least 10 cm, for example 10 cm to 12 cm.

Due to its specific properties, the microfiber composite nonwoven fabric according to the invention is outstandingly suitable as a soundproofing layer and / or as a component of soundproofing layers, for example in the construction sector and / or in motor vehicles. It is also suitable as a barrier layer in home textiles (mite-proof products, hypo-allergenic bedding, cleaning media), as a packaging material or filter medium.

In the method described below, the term identifiers S 'and M' refer to those layers which, after hydrofluidic treatment, become the corresponding layers S and M of the microfiber composite nonwoven fabric according to the invention.

• - Herstellen und/oder Bereitstellen mindestens einer ersten Lage S', die schmelzgesponnene und zu einem Vlies abgelegte Verbundfilamente enthält und/oder eines die Lage S' als Oberflächenlage umfassendes Vlieskomposits;
• - Aufbringen mindestens einer zweiten Lage M', die Schmelzblasfasern enthält, auf die Lage S' und/oder auf diejenige Seite des Vlieskomposits, das die Lage S' als Oberflächenlage aufweist unter Ausbildung eines die Lagen S' und M' aufweisenden Vlieskomposits; und/oder
• - Aufbringen mindestens eines die Lage M' als Oberflächenlage umfassenden Vlieskomposits, auf die Lage S', und/oder auf diejenige Seite des Vlieskomposits, das die Lage S' als Oberflächenlage aufweist, jeweils derart, dass M' und S' benachbarte Lagen bilden unter Ausbildung eines die Lagen S' und M' aufweisenden Vlieskomposits;
• - Hydrofluidbehandlung des die Lagen S' und M' aufweisenden Vlieskomposits, wodurch die Verbundfilamente der ersten Lage S' zumindest teilweise zu Elementar-Filamenten mit einem mittleren Titer von weniger als 1 dtex, gesplittet und gleichzeitig verfestigt und mit den Schmelzblasfasern der zweiten Lage M' zu einem Lagenverbund verbunden werden und wobei die Schmelzblasfasern der Lage M' zumindest teilweise in die Lage S' eindringen.

The invention further comprises a process for producing the microfiber composite nonwoven fabric according to the invention, comprising the following steps:

• Producing and / or providing at least one first layer S 'containing melt-spun composite filaments deposited to a nonwoven and / or a nonwoven composite comprising the layer S' as a surface layer;
• Applying at least one second layer M 'containing meltblown fibers to the layer S' and / or to that side of the nonwoven composite comprising the layer S 'as a surface layer to form a nonwoven composite comprising the layers S' and M '; and or
• Applying at least one nonwoven composite comprising the layer M 'as a surface layer, to the layer S', and / or to that side of the nonwoven composite comprising the layer S 'as the surface layer, in each case such that M' and S 'form adjacent layers Forming a nonwoven composite comprising the layers S 'and M';
• Hydrofluidic treatment of the nonwoven composite comprising layers S 'and M', whereby the composite filaments of the first layer S 'are at least partially split into elementary filaments having an average titre of less than 1 dtex, and simultaneously solidified and melt-fused with the second layer M' are connected to a layer composite and wherein the melt blown fibers of the layer M 'at least partially penetrate into the layer S'.

To produce the first layer S ', the composite filaments can be deposited, for example, by mechanical and / or pneumatic deflection, wherein at least two of these types of deflection can be combined, and by spinning onto an endless treadmill. According to a preferred embodiment of the invention, the composite filaments are dyed by spin dyeing.

The layer S 'can be preconsolidated, for example by mechanical consolidation, in particular needling and / or thermofusion, in particular calendering. In this variant, a pre-consolidation of the first layer before the targeted separation of the uniform composite filaments in elementary filaments.

Instead of the first layer S 'it is also possible to use a nonwoven composite which comprises at least one further layer and the layer S' as the surface layer. In this case, the at least one further layer of the nonwoven composite is advantageously the further layer C described in relation to the composite nonwoven fabric according to the invention. The connection between the first layer S 'and the at least one further layer can take place in a conventional manner, for example by means of sewing, joining, gluing ,

In the next step, a layer M 'containing meltblown fibers is applied to the layer S' and / or to that side of the nonwoven composite comprising the layer S 'as a surface layer to form a nonwoven composite comprising the layers S' and M '.

Alternatively, a nonwoven composite comprising the layer M 'as a surface layer can also be applied to the layer S' and / or to that side of a nonwoven composite which has at least one further layer and the layer S 'as the surface layer. In this case, the at least one further layer of the nonwoven composite is advantageously the further layer C described in relation to the composite nonwoven fabric according to the invention. The application takes place in each case such that M 'and S' form adjacent layers to form a layer S 'and M' Vlieskomposits.

In this case, the step of applying layers according to the invention means that they are arranged in prefabricated form on one another and / or that at least one layer is produced directly on another, for example by melt spinning. Preferably, the layer M 'has a thickness DIN EN ISO 9073-2 from 0.1 mm to 0.4 mm, preferably from 0.15 mm to 0.30 mm.

The meltblown fiber-containing layer M 'may be prepared in a conventional manner, for example, by extruding a molten thermoplastic material through a plurality of fine, preferably circular, die capillaries as molten fibers in a high velocity gas (preferably air). By doing so, the diameter of the fibers can be reduced. Thereafter, the meltblown fibers may be carried by the high velocity gas stream and deposited on the first layer S 'to form the ply composite.

Also conceivable is the separate introduction of the at least one further layer C in the microfiber composite nonwoven fabric. For this purpose, the at least one layer C is advantageously applied to the layers S ', M' and / or to a nonwoven composite comprising the layers S 'and M' before the hydrofluidic treatment such that the at least one layer C has one and / or both outer layers represents the formed nonwoven composite.

The nonwoven composite comprising layers S 'and M' is then subjected to a hydrofluidic treatment in which the composite filaments are at least partially split into elementary filaments having an average titre of less than 1 dtex and simultaneously solidified and bonded to the meltblown fibers, the fiber components of Position M 'at least partially in the situation S' penetrate.

The hydrofluidic treatment of the layer composite advantageously takes place in that the optionally preconsolidated layer composite is subjected at least once on each side to high-pressure fluid jets, preferably high-pressure jets of water. As a result, a composite nonwoven fabric according to the invention having suitable porosity properties and uniformity can be obtained and the degree of splitting of the composite filaments can be adjusted in a targeted manner.

As particularly favorable water jet pressures of 150 bar to 250 bar, preferably from 200 bar to 220 bar have been found in this step.

As explained above, in order to facilitate the separation into the elementary filaments, the composite filaments may have a central opening, in particular in the form of a tubular elongated cavity, which may be centered with respect to the central axis of the composite filaments. By this arrangement, the close contact between the elementary filaments, which are formed by the inner angle of the gaps or circular cutouts, before separation of the elementary filaments, as well as the contact in this range of different elementary filaments made of the same polymer material, reduce or avoid.

In addition, the strength and the mechanical resistance of the composite nonwoven fabric can be significantly increased if it is provided that the elementary filaments are bonded to one another by a thermofusion.

This thermofusion can be carried out with the composite layer after the hydrofluidic treatment.

In a preferred embodiment for producing the microfiber composite nonwoven fabric according to the invention, the layer S 'and / or a nonwoven composite comprising the layer S' as a surface layer is solidified by thermofusion already prior to the hydrofluidic treatment.

Prefixing of the composite filaments can thereby reduce the pressure to be used in the hydrofluidic treatment.

In this case, the thermal fusion in a conventional manner, for example, by hot calendering with heated, smooth or engraved rolls (calendering), by pulling through a hot air tunnel furnace and / or by pulling on a hot air flow through the drum.

As an alternative or in addition to the thermofusion, bonding of the composite nonwoven fabric and / or the layer S 'can be carried out separately by applying a binder contained in a dispersion or in a solution or pulverulent binder.

Furthermore, the layer composite can also by a chemical treatment (as described for example in the French Patent No. 2,546,536 the Applicant is described) and / or solidified by a thermal treatment, which leads to a controlled shrinkage, at least a portion of the elementary filaments, after their optionally carried out separation. This results in a shrinkage of the fabric in the width and / or longitudinal direction.

Further, after the hydrofluidic treatment, the composite layer may be subjected to chemical type bonding or finishing such as anti-pilling treatment, hydrophilization or hydrophobing, antistatic treatment, refractory treatment treatment and / or tactile properties modification, or gloss, a mechanical treatment such as roughening, sanforizing, emery or a tumbler treatment and / or a change appearance treatment such as dyeing or printing.

Advantageously, the layer composite is subjected to a calendering to increase its abrasion resistance after the hydrofluidic treatment. For this purpose, the split and solidified composite nonwoven fabric is passed through heated rollers, of which at least one roller can also have elevations, which lead to a selective fusion of the filaments with each other.

1. I. Flächengewicht (g/m²): EN 29073
2. II. Dicke (mm): DIN EN ISO 9073-2 , Gewicht 12,5 cN/cm, Fläche 10 cm²
3. III. Luftdurchgang LD (l/m²sec): DIN EN ISO 9237 , Schallkennimpedanz afr berechnet aus LD gemäß (Vordruck [mbar]*1000/LD) in rayls
4. IV. Zugfestigkeit und -dehnung: EN 29073 T3
5. V. Heisszugfestigkeit und -dehnung: EN 29073 T3, T = 180°C
6. VI. ÖTI Test:
   • Um die Verformungseigenschaften unter Hitze (Tiefziehfähigkeit) zu bewerten, werden fixierte Prüflinge der Substrate in einem einfachen Versuchsaufbau (ÖTI Test) mittels eines auf 160°C aufgeheizten runden Stempels verformt (Kugeldurchmesser 9 cm, absolute Prüflingsgröße 24 cm Durchmesser, frei verformbare Prüflingsgröße 20 cm). Dabei werden die Weglänge bis zur Beschädigung in cm, die bei einer Verformung von 5% und 9% auftretende Kraft in N, sowie die zur Verformung maximal aufzuwendende Kraft in N als Messgrößen zur Bewertung der Materialeigenschaften herangezogen. Eine große Weglänge bei 160°C bei entsprechender (niedriger) Kraft bedeutet demnach positive Verformungseigenschaften unter Hitzeeinwirkung (Tiefziehfähigkeit).
7. VII. Mean flow pore diameter (µm): ASTM E 1294 (1989), Probengröße 21 mm, Testflüssigkeit Galden HT230, Messung bei Raumtemperatur
8. VIII. Fraktionsabscheidegrad: EN 1822-3 (2011), Prüfstaub nach ISO 12103-1 A2 Temperatur 23 °C ± 3°C, rel. Feuchte 50 % ± 5%; Anströmgeschwindigkeiten 5 cm/sec und 50 cm/sec; Probenzustand ungewaschen
9. IX. Schallabsorbtionsgrad: DIN EN ISO 10534-1: 2001-10 ; Luftraum 30 mm

   MD =

   Maschinenrichtung

   CD =

   Querrichtung

   SB =

   spunbond

   MF =

   Mikrofaser

The following measurement methods were used to determine the parameters determined in this invention:

1. I. Basis weight (g / m ² ): EN 29073
2. II. Thickness (mm): DIN EN ISO 9073-2 , Weight 12.5 cN / cm, area 10 cm ²
3. III. Air passage LD (l / m ² sec): DIN EN ISO 9237 , Sound impedance afr calculated from LD according to (form [mbar] * 1000 / LD) in rayls
4. IV. Tensile strength and elongation: EN 29073 T3
5. V. Hot tensile strength and elongation: EN 29073 T3, T = 180 ° C
6. VI. ÖTI test:
   • In order to evaluate the deformation properties under heat (thermoformability), fixed specimens of the substrates in a simple test setup (ÖTI test) by means of a heated to 160 ° C round punch deformed (ball diameter 9 cm, absolute Prüflingsgröße 24 cm diameter, freely deformable Prüflingsgröße 20 cm ). In this case, the path length up to the damage in cm, the force in N at a deformation of 5% and 9%, and the maximum force to be applied for deformation in N are used as parameters for evaluating the material properties. A long path length at 160 ° C with corresponding (lower) force thus means positive deformation properties under heat (thermoformability).
7. VII. Mean flow pore diameter (μm): ASTM E 1294 (1989), sample size 21 mm, test liquid Galden HT230, measurement at room temperature
8. VIII. Fractional efficiency: EN 1822-3 (2011), test dust according to ISO 12103-1 A2 Temperature 23 ° C ± 3 ° C, rel. Humidity 50% ± 5%; Flow velocities 5 cm / sec and 50 cm / sec; Sample state unwashed
9. IX. sound absorption: DIN EN ISO 10534-1: 2001-10 ; Air space 30 mm

   MD =

   machine direction

   CD =

   transversely

   SB =

   spunbond

   MF =

   microfiber

In the following the invention will be explained in more detail with reference to several examples.

Example 1: Production of Microfiber Composite Nonwovens According to the Invention

There are 7 composite microfiber nonwoven fabrics according to the invention, as described in the table below, prepared. Table 1: Microfiber composite nonwovens 1-7 (S '= ply composite filaments; M' = ply melt blown filaments; C = ply carded staple fibers; CK = ply carded, thermally bonded staple fibers); x = number of layers used. Single Location Weight [g / m ² ] 40 60 100 28 80 80 polymer PET / PA PET / PA PET / PA PBT aramid aramid MF composite fiber 16 PIE SB 16 PIE SB 16 PIE SB meltblown card card / cal. Type Location MF composite S ' S ' S ' M ' C CK 1 x x SM 2 xx x SMS 3 xx xx SMMS 4 x x xx SMMS 5 x xx x SMMC 6 x xx x x CMMSCK 7 x xx xx CMMSC

As can be seen from the above table, microfiber composite nonwovens can be produced according to the invention starting from individual layers S ', M', C and CK as well as nonwoven composites comprising layers S ', M', C and CK.

By varying the type, number and arrangement of the individual layers used, it is possible to obtain a multiplicity of microfiber composite nonwovens having a wide variety of properties.

Example 2: Determination of textile-physical parameters of the microfiber composite nonwovens 1-7

Textile-physical data of the 7 microfiber composite nonwovens according to the invention are determined and shown in the following table. Table 2: Textile Physical Description of Embodiments 1-7; the acoustic characteristic impedance of 1 rayl corresponds to 1 N s / m ³ in SI units. MF composite Weight LD LD afr thickness HZK HZK HZD HZD 100 Pa / 5cm ² 200 Pa / 20 cm ² 200 Pa MD CD MD CD [g / m ² ] [l / m ² sec] [l / m ² sec] [Rayls] [Mm] [N / 50mm] [N / 50mm] [%] [%] EN 29073 angel. DIN EN ISO 9237 DIN EN ISO 9237 DIN EN ISO 9073-2 EN 29073 T3 EN 29073 T3 EN 29073 T3 EN 29073 T3 1 70 289 454 440 0.39 127 85 51 60 2 111 86 195 1025 0.46 202 205 47 73 3 138 52 105 1904 0.55 273 185 52 67 4 207 29 61 3278 0.81 430 398 61 77 5 286 38 79 2531 1.16 742 460 52 65 6 256 39 76 2631 1.19 697 373 48 72 7 258 38 78 2564 1.23 678 361 49 68

The results of tests V - VI are shown in the following tables: TABLE 3 Hot drawing test of working examples 1-4; Module values at 180 ° C in direct comparison with conventional microfiber based single layers in the weight range 40 - 100 g / m ² . Deformation [%] at 180 ° C 3 5 10 15 20 30 3 5 10 15 20 30 exam EN 29 073 T3 orientation MD CD unit [N / 50 mm] [N / 50 mm] 1 5.0 6.9 11.2 16.2 21.4 32.5 3.0 3.6 6.1 8.4 11.7 19.7 2 10.2 13.8 22.2 30.7 39.8 60.0 4.2 5,7 9.8 14.5 20.5 34.3 3 12.8 16.8 26.8 37.2 47.7 70.5 4.4 5.9 10.9 15.6 21.8 36.8 4 21.6 30.7 50.8 71.6 93.4 141.6 8.9 12.4 21.3 31.7 43.3 141.6 MF 40 4.7 6.3 9.8 13.5 17.4 25.8 2.6 3.0 4.2 5.6 7.5 12.1 MF 60 7.1 9.8 15.4 21.0 27.1 40.1 3.8 4.7 7.1 9.9 13.3 22.0 MF 80 9.2 12.7 19.4 26.3 33.8 50.2 4.4 5,7 8.7 12.2 16.5 27.7 MF 100 15.4 20.7 30.4 40.0 50.6 73.6 6.1 8.0 12.4 17.2 23.0 38.0

The materials MF (microfibers) reproduced for comparison in Tables 3, 4 and 5 represent the single layer S described in relation to the composite microfiber nonwoven according to the invention of melt-spun and non-woven composite filaments. The reproduced data correspond to this single layer S after hydrofluidic treatment. Table 4: hot tensile test / maximum tensile strength and maximum tensile strain of the embodiments 1-4 at 180 ° C in direct comparison with conventional microfiber based individual layers in the weight range 40 - 100 g / m ² . Hot tensile tests @ 180 ° C HZK / HZD Prüfunq orientation MD CD unit [N / 50mm] [%] [N / 50mm] [%] 1 73.4 63.7 52.7 64.2 2 140.4 71.4 121.2 80.8 3 152.5 66.8 129.3 83.8 4 313.4 69.1 239.3 84.4 MF 40 42.8 50.5 29.5 61.9 MF 60 67.2 50.8 56.1 62.7 MF 80 94.8 56.8 82.4 68.6 MF 100 139.3 59.2 113.7 72.0 Table 5: ÖTI / deformation test of the embodiments 1-4 at 160 ° C in direct comparison with conventional microfiber based individual layers in the weight range 40 - 100 g / m ² . measurand OTI Prüfunq 160 ° C orientation Max. Force Path M 5cm M9 cm unit [N] [cm] [N] [N] 1 570.4 10.2 76.7 429.8 2 975.5 10.0 99.2 742.6 3 1,049.8 10.5 84.9 694.0 4 1,840.7 10.3 154.3 1,281.3 MF40 255.8 7.9 61.5 104.2 MF60 440.3 8.3 97.3 243.9 MF80 600.0 8.6 98.6 486.9 MF100 805.2 8.7 122.6 688.6

The results of tests VII-VIII are shown in the following tables: Table 6: Determination of Porosity Properties of Exemplary Embodiments 1-4. number composite Weight afr bubble point mean flow pore diameter smallest pore diameter largest pore diameter [g / m ² ] [Rayls] [.Mu.m] [.Mu.m] [.Mu.m] [.Mu.m] 1 SM 70 440 121 16.8 10.94 141.3 2 SMS 111 1025 47 9.3 6.55 50.5 3 SMMS 138 1904 36.8 7.3 5.26 41.6 4 SMMS 207 3278 22.9 7.3 2.65 24.4 Table 7: Pressure drop and fraction separation efficiency of the embodiments 1-4 at particle sizes of 0.5, 1, 3, 5 and 10 microns. number Δp [Pa] Fractional efficiency grade [%] for particle size [μm] 0.5 1 3 5 10 1 21 67 72 86 91 94 2 60 94 96 99 > 99.5 > 99.5 3 90 97 98 > 99.5 > 99.5 > 99.9 4 139 > 99.5 > 99.9 > 99.9 > 99.9 > 99.9 Table 8: Filtration efficiency of the embodiments 1-4 at particle sizes of 1 micron - 4.7 microns and> 5 microns. number 1 2 3 4 efficiency 1-4,7 μm [%] 72 96 98 > 99.9 efficiency > 5 μm [%] 91 99 99 > 99.9

The results obtained with regard to fractional efficiencies show that the limit values of TÜV Rheinland are complied with and that embodiments 1 to 4 are suitable for producing hypo-allergenic bed linen in the unwashed state.

list of figures

• 1 and 2 : Hot tensile test of embodiment 1; Module values at 180 ° C in direct comparison with conventional microfiber based single layers in the weight range 40 and 60 g / m ² .
• 3 : Sound Absorbance / Impedance of the embodiment 1 in comparison to the individual layers used in Example 1.
• 4 : Sound absorption / impedance of the embodiment 1 compared to individual layers of type S after hydrofluidic treatment (MF = microfiber).
• 5 3 shows a scanning electron microscopically generated cross-sectional image of a microfiber composite nonwoven fabric according to the invention consisting of a layer S, a layer M and a layer C.

figure description

1 and 2 show results of Heisszugversuches of Embodiment 1 in the longitudinal and transverse directions, and the specific module values at 180 ° C in direct comparison with conventional microfiber based individual layers in the weight range 40 and 60 g / m ² .

3 shows the Schallabsorbtionsgrad / impedance of the embodiment 1 in comparison to the individual layers used in Example 1. It turns out that the special combination of split fibers with meltblown fibers is unexpectedly favorable, especially in terms of sound absorption. In a microfiber composite nonwoven fabric SM according to the invention is apparent when considering the Schallabsorbtion surprisingly synergistic effect of split fibers and meltblown fibers. In this case, the sound absorption coefficient of the layer composite SM produced by hydrofluid treatment over the frequency range is significantly above the level expected by pure combination of the starting materials or evaluation of the air passage resistance to be measured (440 rayls in the embodiment 1). This result is particularly surprising in that it was to be expected that the strong barrier effect usually produced by meltblown fibers leads to disproportionately high air passage resistance and thus proves to be unfavorable for producing a balanced sound absorption profile.

4 shows the Schallabsorbtionsgrad / impedance of the embodiment 1 compared to individual layers of the type S after hydrofluidic treatment (MF = microfiber). As in 4 becomes clear, the special combination of the split fibers with the melt blown fibers in the sense of sound absorption proves to be unexpectedly favorable. In a microfiber composite nonwoven fabric SM according to the invention (basis weight 70 g / m ² ), a surprisingly synergistic effect of split fibers and meltblown fibers is evident when considering the sound absorption compared to purely microfiber-based nonwoven layers in the basis weights of 40 and 80 g / m ² . The sound absorption coefficient of the layer composite SM produced by hydrofluid treatment at 70 g / m ^{2 basis} weight is significantly above the level of the sound absorption coefficient of the microfiber-based nonwoven layer S in the basis weight of 80 g / m ² .

The results determined with regard to the sound absorption properties - especially taking into account the material properties under load when hot - show that microfiber composite nonwoven fabrics according to the invention can be used to particular advantage for the production of acoustically effective components.

Without specifying a mechanism, it is assumed that the good performance of the nonwoven fabric according to the invention is achieved by thorough mixing of the individual components.

5 shows a scanning electron microscopically generated cross-sectional image of a microfiber composite nonwoven fabric according to the invention consisting of a layer S, a layer M and a layer C (staple fibers). One recognizes a clear mixing of all three layers.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 3849241 [0036]
• FR 2546536 [0079]

Cited non-patent literature

• DIN EN ISO 9073-2 [0048, 0066, 0082, 0087]
• DIN EN ISO 9237 [0082, 0087]
• ISO 12103-1 A2 [0082]
• DIN EN ISO 10534-1: 2001-10 [0082]

Claims (15)

A microfiber composite nonwoven fabric comprising at least one ply S containing a first fiber component and at least one ply M containing a second fiber component, the second fiber component at least partially penetrating the ply S, the fibers of the first fiber component being melt spun and bonded to a first fiber component Nonwoven deposited composite filaments which are at least partially split into elementary filaments having an average titer of less than 1 dtex, are split and solidified, characterized in that the fibers of the second fiber component are meltblown fibers. Microfiber composite nonwoven according to Claim 1 , characterized by an average pore diameter of less than 20 microns and / or a smallest pore diameter less than 11 microns. Microfiber composite nonwoven according to Claim 1 or 2 , characterized in that the first fiber component has at least partially penetrated into the layer M. Microfiber composite nonwoven fabric according to one or more of the preceding claims, characterized in that the at least partial penetration of the second fiber component into the layer S and / or the first fiber component in the layer M by means of hydrofluidic treatment, in particular by means of hydroentanglement was performed. Microfiber composite nonwoven according to one or more of the preceding claims, characterized in that the denier of the elementary filaments of 0.01 dtex to 0.8 dtex. Microfiber composite nonwoven fabric according to one or more of the preceding claims, characterized in that the proportion of the elementary filaments of the first fiber component, based on the total weight of the nonwoven fabric is at least 20 wt.%. Microfiber composite nonwoven fabric according to one or more of the preceding claims, characterized in that the meltblown fibers are formed from polymers having an MFI value according to ISO 1133 of 100 to 3000 g / 10 min. Microfiber composite nonwoven fabric according to one or more of the preceding claims, characterized in that the meltblown fibers have a fiber titer of 0.5 .mu.m to 5 .mu.m, preferably from 1.0 .mu.m to 4 .mu.m, in particular from 1.8 .mu.m to 3.6 .mu.m , A microfiber composite nonwoven fabric according to one or more of the preceding claims, characterized in that the proportion of meltblown fibers in the microfiber composite nonwoven fabric is at least 20% by weight, based on the total weight of the microfiber composite nonwoven fabric. Microfiber composite nonwoven according to one or more of the preceding claims, characterized in that the microfiber composite nonwoven fabric has at least one further layer C containing staple fibers and / or filaments, wherein the fibers and / or filaments of the layers S, M and / or C preferably at least partially penetrate each other. Microfiber composite nonwoven fabric according to one or more of the preceding claims, characterized by a degree of sound absorption (1000 Hz) of more than 0.4 and / or by a sound absorption coefficient (2000 Hz) of more than 0.8 and / or by a sound absorption coefficient (2000 Hz ) of more than 0.8, each at a basis weight below 150 g / m ² . Microfiber composite nonwoven fabric according to one or more of the preceding claims, characterized by a mean flow pore diameter of less than 20 microns at a basis weight below 200 g / m ² . Microfiber composite nonwoven fabric according to one or more of the preceding claims, characterized by a Fraktionsabscheidegrad (particle size 1-4.7 mm) of more than 60% and / or by a Fraktionsabscheidegrad (particle size> 5 mm) of more than 80. Process for producing a microfiber composite nonwoven according to one or more of the preceding claims comprising the following steps: Producing and / or providing at least one first layer S 'which contains melt-spun and non-woven composite filaments and / or a nonwoven composite comprising the layer S' as a surface layer; Applying at least one second layer M 'containing meltblown fibers to the layer S' and / or to that side of the nonwoven composite comprising the layer S 'as surface layer, forming a nonwoven composite comprising the layers S' and M '; and / or applying at least one nonwoven composite comprising the layer M 'as a surface layer to the layer S', and / or to that side of the nonwoven composite comprising the layer S 'as a surface layer, such that M' and S 'are adjacent layers form to form a nonwoven composite comprising the layers S 'and M'; Hydrofluidic treatment of the nonwoven composite comprising layers S 'and M', whereby the composite filaments of the first layer S 'are at least partially split into elementary filaments having an average titre of less than 1 dtex, and simultaneously solidified and melt-fused with the second layer M' are connected to a layer composite and wherein the melt blown fibers of the layer M 'at least partially penetrate into the layer S'. Use of a microfiber composite nonwoven fabric according to one or more of Claims 1 to 13 as sound insulation layer and / or as part of sound insulation layers, for example in the construction sector and / or in motor vehicles; as a barrier layer in home textiles (mite-proof products, hypo-allergenic bedding, cleaning media), as packaging material and / or filter medium.

Images